<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			#a{
				display: flex;
			}
			#a div:nth-child(1){
				background-color: #7777D4;
				flex: 0 0 200px;
				height: 100px;
			}
			#a div:nth-child(2){
				background-color: #7FFFD4;
				flex: 1 1 auto;
				height: 100px;
			}
			#a div:nth-child(3){
				background-color: #F08080;
				flex: 0 0 200px;
				height: 100px;
			}
			@media screen and (min-device-width: 500px) and (max-device-width: 900px){
				#a div:nth-child(2){
					background-color: #FFFF00;
				}
			}
		</style>
	</head>
	<body>
		<div id="a">
			<div>1</div>
			<div>1</div>
			<div>1</div>
		</div>
	</body>
</html>
